Salivary Diagnostics

More and better tools for diagnosing human diseases are reaching doctors' offices, but many of the tests require a blood sample. Although most people are happy to endure a needle stick to rule out a dreaded diagnosis, the small costs involved add up when one considers screening entire populations. Furthermore, the need to draw blood makes such tests difficult to provide to people who have limited access to medical care. One solution to both problems is the use of saliva, which is inexpensive, noninvasive and easy to collect and preserve. As David T. Wong explains, saliva is a "mirror of the body" and contains many of the same molecules that clinical scientists use to diagnose disease from a blood sample. Wong is part of the consortium of researchers at UCLA who have analyzed the salivary genome and proteome—the complete collection of expressed genes and proteins contained in saliva. They found that oral cancer and Sjögren's Syndrome, an autoimmune disease, can be diagnosed by examining the levels of specific suites of RNA molecules in saliva. Ongoing studies suggest that this technique can also reveal the presence of breast cancer, pancreatic cancer and type-II diabetes.